A rock with a mass of 5-kg and moving at 20 m/s collides head on with a 10-kg rock. After the collision, both rocks come to rest. Determine the initial velocity of the 10-kg rock.

20. threshold braking in the vehicle's braking system occurs when a. the brake pedal is pushed, heel on floorboard, with full foot pressure. b. the brakes are exerting full braking power, without traction loss. c. the driver begins pushing down the brake pedal, with moderate slowdown. d. the brakes just begin to take hold with a gradual slowdown.

Imagine that someone pushes one marble toward a motionless marble. would there still be action-reaction forces involved in the collision? how might the marbles’ motions be changed? ?

Give an example in which the electrical energy changes to light energy